Single Blog

Table of Contents

These tests are conducted on all electronic/electrical devices and equipment, to make sure they do not make devices next to them malfunction.

These tests are those which are conducted to measure the power and frequency of RF emissions from devices and equipment.

These emissions are categorized as those under 30MHz and over 30MHz, because of the two primary methods of EM emission from equipment, conducted and radiated.

Emission Measuring Instruments

Measuring Receiver

Conformance tests are taken with receivers which are optimized for the purpose of taking EMC measurements. The average cost of measuring a receiver system between 10kHz to 1GHz range is between $15,000-$60,000.

Spot Frequency Receiver-

These are hand-held receivers that the operator uses to take readings of emissions of individual frequencies from the EUT.

FFT/time Domain Receiver-

Fast Fourier Transform is an algorithmic implementation of Fourier Transform that enables the measuring device to take time-domain readings and convert them into real-time frequency spectrum plots.

Spectrum Analyzer-

This is used to record emissions from the EUT in the full frequency spectrum, within the device’s capability. This is used to confirm the frequency range in which sport frequency reception will be required because due to their full spectrum measurement capability these devices have a small amount of error.

Receiver Specifications

These are the parameters on which these devices evaluate, emission performance of the equipment under test. These parameters are defined in CISPR 16-1-1, and MIL-STD-461G, and DEFSTAN 59-411 for military tests.

Transducers

These devices are used to convert the emissions to be measured from the EUT into something which can be displayed onto the screen of the measuring device. These devices are able to convert the four important parameters,

1. Radiated electric field
2. Radiated magnetic field
3. Conducted cable voltage, and
4. Conducted cable current

Into readings which can be displayed on the screen on the receiver. CISPR 16-1-4 is referenced while choosing transducers/antennas for EMC emission testing.

LISNs and probes for cable measurements

Artificial Mains Network. 

These devices are used to conduct voltage emissions tests on the main port. These are required to provide a defined impedance at RF across the measuring point, to test the instrument, and isolate the test circuit from unwanted interference signals on the mains supply.

Artificial Hand

The requirements for this are specified in CISPR 16-1-2. This accessory is used to simulate those devices which are designed for hand-held usage. This accessory is a strip of metal foil, 6cm wide and normally wrapped around that part of the EUT which will be touched by the user’s hand.

Absorbing clamp and CMAD

These devices are used to measure emissions above 30MHz as radiated fields. The standards used to get this apparatus is CISPR 14-1/EN 55014-1.

Current Probe

This is a clamp-on device that is used to measure the amount of current flowing in a cable. The standard used for this is CISPR 22/EN 55022.

Near Field Probes

These probes are used to detect emissions near to culprit device. These devices can be around cylindrical rod or a loop that needs to be taken near the culprit devices to take readings